Regular screening can often detect colorectal cancer early, at which it is most likely to be curable. In many cases, screening can also prevent colorectal cancer altogether. Some polyps, or growths, can be found and fought before they have the chance to turn into cancer.
Types of screening tests
Tests used to screen for colorectal cancer include:
- Guaiac-based fecal occult blood test (gFOBT) and fecal immunochemical test (FIT). In these tests, samples of stool (feces) are checked for blood, which might be a sign of a polyp or cancer.
- Stool DNA test. A sample of stool is checked for certain abnormal sections of DNA (genetic material) from cancer or polyp cells.
- Sigmoidoscopy. A flexible, lighted tube is put into the rectum and lower colon to check for polyps and cancer.
- Colonoscopy. A longer, flexible tube is used to scan the entire colon and rectum.
- Double contrast barium enema. This is an x-ray test of the colon and rectum.
- CT colonography (virtual colonoscopy). This is a type of CT scan of the colon and rectum.
gFOBT, FIT, and stool DNA testing mainly find cancer. Furthermore, they can also detect some polyps.
Sigmoidoscopy, colonoscopy, double-contrast barium enema, and CT colonography are trusted to detect cancer and polyps. Polyps can be removed before turning into cancer, so these tests may effectively prevent colorectal cancer. This is why they are preferred as long as they are available and patients are willing to take them.
Different organizations have made different recommendations for colorectal cancer screenings. Two sets of recommendations are described below. You should talk with your doctor about the best test and time based on your health history and personal cancer risk.
Beginning at age 50, both men and women of average risk should follow one of these testing schedules.
The following tests detect both polyps and cancer:
- Flexible sigmoidoscopy: every five years;
- Colonoscopy: every 10 years;
- DCBE: every five years;
- CT colonography: every five years.
These tests primarily detect cancer:
- Guaiac-based FOBT: every year;
- Fecal immunochemical test: every year;
- Stool DNA test: as often as your doctor recommends.
The U.S. Preventive Health Services Task Force (USPSTF) also has guidelines for colon cancer screening, which differ somewhat from those mentioned above. The USPSTF recommends one of the following testing methods:
- A high-sensitivity FOBT: every year;
- Sigmoidoscopy: every five years, with FOBT testing between tests;
- Colonoscopy: every 10 years.
According to the USPSTF, adults between ages 76 and 85 should not have routine screening because the risks outweigh the benefits, and adults older than 85 can avoid colorectal cancer screening. However, people who have a history of polyps or colorectal cancer have a higher risk of the disease, and screening may still be recommended at an older age.
What you should remember
It is important to note that, regardless of the screening test and schedule, any test that indicates an abnormality should be followed up with a colonoscopy.
Hello Health Group does not provide medical advice, diagnosis or treatment.
Review Date: January 4, 2017 | Last Modified: January 4, 2017
Can colorectal polyps and cancer be found early?. http://www.cancer.org/cancer/colonandrectumcancer/detailedguide/colorectal-cancer-detection. Accessed December 12, 2016.
Colorectal Cancer: Risk Factors and Prevention. http://www.cancer.net/cancer-types/colorectal-cancer/risk-factors-and-prevention. Accessed December 12, 2016.